Strain and curvature optical fiber laser sensor based on an accurate RI-regulated FMF with high modal power balance

• Published in: Optics communications 2023-03, Vol.531, p.129183, Article 129183
• Main Authors: Chang, Yanbiao, Pei, Li, Wang, Jianshuai, Zheng, Jingjing, Shen, Lei, Ning, Tigang, Li, Jing
• Format: Article
• Language: English
• Subjects: Few-mode fiber; Modal interference; Optical fiber laser sensor; Uniform transmission spectrum
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/j.optcom.2022.129183

In this paper, a ring fiber laser sensor based on a three layered-core few modes fiber (TL-FMF) is proposed. The home-made TL-FMF is spliced with two pieces of single mode fiber (SMF) at both sides as the sensing and filtering component. In the TL-FMF, an intermediate with higher refractive index (RI) is sandwiched between a central dip and a sub-high RI layer. Due to the special RI, the TL-FMF has an equidistant modal effective RI difference and a balanced modal power of different modes, enabling a highly uniform interference spectrum. Then applying the TL-FMF in proposed ring fiber laser sensor, the sensing experimental results show that its sensitivities in strain and curvature are −2.78 pm/με and −6.17 nm/m−1, respectively, and shows an excellent characteristic of temperature insensitivity. This fiber laser sensor implements the dual-parameter measurement with anti-cross sensitivity, which offers a promising candidate in fiber fabrication monitoring, deformation measurement and bending detection. •An accurate RI-regulated FMF with modal power balance is proposed.•A ring fiber laser sensor based on this FMF is proposed.•The sensitivities in strain and curvature are −2.78 pm/με and −6.17 nm/m−1.•The laser sensor shows an excellent temperature insensitivity.